media: v4l: async: Support fwnode endpoint list matching for subdevs

Support matching V4L2 async sub-devices based on particular fwnode
endpoint. This makes it possible to instantiate multiple V4L2 sub-devices
based on given fwnode endpoints from a single device, based on driver
needs.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de> # imx6qp
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> # rcar + adv746x
Tested-by: Aishwarya Kothari <aishwarya.kothari@toradex.com> # Apalis i.MX6Q with TC358743
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> # Renesas RZ/G2L SMARC
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

2 files changed, 36 insertions, 2 deletions

diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index 8670b8e44851..41a9c4bada8a 100644
--- a/include/media/v4l2-async.h
+++ b/include/media/v4l2-async.h
@@ -126,6 +126,18 @@ struct v4l2_async_notifier {
 };
 
 /**
+ * struct v4l2_async_subdev_endpoint - Entry in sub-device's fwnode list
+ *
+ * @async_subdev_endpoint_entry: An entry in async_subdev_endpoint_list of
+ *				 &struct v4l2_subdev
+ * @endpoint: Endpoint fwnode agains which to match the sub-device
+ */
+struct v4l2_async_subdev_endpoint {
+	struct list_head async_subdev_endpoint_entry;
+	struct fwnode_handle *endpoint;
+};
+
+/**
  * v4l2_async_debug_init - Initialize debugging tools.
  *
  * @debugfs_dir: pointer to the parent debugfs &struct dentry
@@ -216,6 +228,24 @@ __v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier,
 					 sizeof(type)))
 
 /**
+ * v4l2_async_subdev_endpoint_add - Add an endpoint fwnode to async sub-device
+ *				    matching list
+ *
+ * @sd: the sub-device
+ * @fwnode: the endpoint fwnode to match
+ *
+ * Add a fwnode to the async sub-device's matching list. This allows registering
+ * multiple async sub-devices from a single device.
+ *
+ * Note that calling v4l2_subdev_cleanup() as part of the sub-device's cleanup
+ * if endpoints have been added to the sub-device's fwnode matching list.
+ *
+ * Returns an error on failure, 0 on success.
+ */
+int v4l2_async_subdev_endpoint_add(struct v4l2_subdev *sd,
+				   struct fwnode_handle *fwnode);
+
+/**
  * v4l2_async_connection_unique - return a unique &struct v4l2_async_connection
  *				  for a sub-device
  * @sd: the sub-device
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index a8078ae99596..a012741cc876 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1022,6 +1022,8 @@ struct v4l2_subdev_platform_data {
  *	    either dev->of_node->fwnode or dev->fwnode (whichever is non-NULL).
  * @async_list: Links this subdev to a global subdev_list or
  *		@notifier->done_list list.
+ * @async_subdev_endpoint_list: List entry in async_subdev_endpoint_entry of
+ *				&struct v4l2_async_subdev_endpoint.
  * @subdev_notifier: A sub-device notifier implicitly registered for the sub-
  *		     device using v4l2_async_register_subdev_sensor().
  * @asc_list: Async connection list, of &struct
@@ -1065,6 +1067,7 @@ struct v4l2_subdev {
 	struct device *dev;
 	struct fwnode_handle *fwnode;
 	struct list_head async_list;
+	struct list_head async_subdev_endpoint_list;
 	struct v4l2_async_notifier *subdev_notifier;
 	struct list_head asc_list;
 	struct v4l2_subdev_platform_data *pdata;
@@ -1382,8 +1385,9 @@ int __v4l2_subdev_init_finalize(struct v4l2_subdev *sd, const char *name,
  * v4l2_subdev_cleanup() - Releases the resources allocated by the subdevice
  * @sd: The subdevice
  *
- * This function will release the resources allocated in
- * v4l2_subdev_init_finalize.
+ * Clean up a V4L2 async sub-device. Must be called for a sub-device as part of
+ * its release if resources have been associated with it using
+ * v4l2_async_subdev_endpoint_add() or v4l2_subdev_init_finalize().
  */
 void v4l2_subdev_cleanup(struct v4l2_subdev *sd);